<h2>DESCRIPTION</h2>

<em>i.spectral</em> displays spectral response at user specified 
locations in images.

<h2>NOTES</h2>

This script needs gnuplot to be installed.


<h2>EXAMPLE</h2>

Analysis of LANDSAT TM7 channels (North Carolina dataset):

<div class="code"><pre>
g.region raster=lsat7_2002_10 -p
i.spectral -g input=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70 \
           coordinates=636069,215440,637958,223393,633277,223605
</pre></div>

<center>
<img src="i_spectral.png" border=1><br>
Spectral plot of 3 different land cover types: (1) water, (2) green vegetation, and (3) highway
</center>


<p>
North Carolina sample dataset:

<div class="code"><pre>
g.region raster=lsat7_2002_10 -p
LIST=`g.list type=raster pattern="lsat7_2002_[1-5,7]0" separator=","`
i.spectral input=$LIST coordinates=637502.25,221744.25
</pre></div>

This will search all LANDSAT map for 2002 but select only the B, G, R, 
NIR, and MIR channels.


<h2>SEE ALSO</h2>

<em>
<a href="d.where.html">d.where</a>,
<a href="r.what.html">r.what</a>
</em>

<h2>AUTHOR</h2>

Markus Neteler<br>
Francesco Pirotti

<!--
<p>
<i>Last changed: $Date$</i>
-->
